Manufacture of meat-curing salt composition



United States Patent nitrogen-containing salt selected from the group consisting of alkali metal nitrite, alkali-metal nitrate, and mixtures thereof. v p

Curing salt compositions are commonly shipped in large drums from a supplier to a meat packer, who removes portions from the drums for immediate use. vFor a long time past, such compositions were made by mechanically mixing crystals of the separate salt ingredients. Complaints by government control authorities arose as a result of using such a mixture. The content of the nitrite salt used in curing is limited by such authorities. It was ascertained that in shipping, andindistributing suchbulkquantities of the mechanical mixture, gravitational separation frequently took ;place with the result that there were formed portions relativelydeficient and relatively richer in nitrite salt. excess use of nitrite in the curing process.

It is known thatwhen such a mixture isvery finely ground, the danger of separation is minimized, but other difliculty is encountered. Very fine particles tend to cake merely due to their size. This tendencymakes the particles less mobile, thus minimizings'eparation'. The longer such a fine-ground mass stands, the harder it cakes, making it morediificult to remove apportion of the cake for use.

It has been found that the ingredients as a mechanical mixture can be bonded to.a unified form byelf'ective mechanical pressure, so that the unified form may be reduced to desired sizesfor various commercial practices Without a change of composition.

It is the general object of "the invention to produce a granular mass of polycrystalline aggregates consisting essentially of homogeneous sodium chloride crystals and the selected nitrogen-containing curing salt.

Use of the richer portions resulted in 3,164,489 Patented Jan. 5, 1965 is desired the agglomerated material is ground or com- -minuted toa desiredfineness short of one which cakes on standing, and preferably 'to 'a fineness coarser than the 1particle-size-distribution of the .material subjected to compaction. Comminution :is best done and controlled by on the caked forms which are dry. or which have not more than 2%.content of moisture, andpreferably-less than 1% content of moisture. i V

Caking-may-beelfected in one Way by mechanically squeezing together the particles of a fine-'groundmixture. This may be done by mechanically compressing the individual original crystals into sheet, cake, pellet, or briquette form.

One wayis to extrude a rod like form and to chop off pellets as extruded. Another way is'to pass. a mass of the original crystals through the .nip of heavycompression rolls, exerting heavy pressure, so that sheet-like forms are producedof thickness, for-example $4 to Az-inch. Such forms may be further fragmented to facilitate further comminution as described.

.In curingmeat a considerable quantity of sodium chlorideis used with a small quantity of curing salt. It is a -conventional practice to compound sodium chlorideand the curing salt for use as an ingredient inprocessingmeat,

usually supplemented by additional sodium chloride.

It is a particular objectof the invention to prepare a granular salt composition of the-typedescribed with a particle-size-distribution such that all the size-fractions thereof are substantially uniform inchemical composition; It is a particular object of the invention to produce a free-flowing granular form of such a composition.

The preferredprocess istoprepare a finelyedivided or fine-ground uniform mixture containing the salt ingredh ents, mechanicallytoapply pressure-in a mannerto'prm -is suitably finely-divided orfine-ground, is purposely caked or agglomerated to eliminate-the small-size particles and to bond the mass to a unified Whole. Cake or caked forms are thus produced. When a granular free-flowing product measured by reference to thernitrite content.

Therefore, the composition of the presentinven'tion has no more sodium chloride combined withthe curing salt than is to be used for the meat with the curing salt content.

A typical curing salt composition-permitting use of supplemental-sodium;chlorideis chosen forthe purpose only of illustration, as follows:

Sodium nitrite 6 Sodium nitrate 4 This composition is hereinafter referred to as -6-4. Nitrite salt is the chief ingredient with which certain Federal regulations are concerned, and the uniformity of the composition as referred to in the present application is In the typical composition given above, the theoretical content of 'nitrite is 6%. The Federal regulations, in recognition h of problems in manufacture, permit deviations up to 10% 7 from the theoretical content, when the theoretical amount crystals are available in diiferent grades of fineness, identified as fine salt, fine flake salt, and flake salt. Table I below shows the particle-size-distribution of these three 'salt grades and of commercial sizes of nitrate and nitrate salt crystals.

The above salt supplies were blended to a 90-6-4 composition and the blend fractionated on the same set of screens. The nitrite contents of the fractions are given 'in Table II which shows poor uniformity in chemical composition, indicative of separation in shipping.

Table II Percent Nitrite Salt in Fractions Composition N o.

' NaCl On 50 On 100' On 200 Thru 200 Mechanical mixtures of 90-6-4 were made using the same grades of sodium chloride crystals and finer grades of the nitrite and nitrate salts, of which the particle-sizedistributions are given in Table III.

Table III Percent in Fractions Ingredient On 50 On 100 On 200 Thru 200 Sodium Nitrate". 0 2 13 85 These mechanical mixtures were then fractionated on the same screens and the nitrite contents of the fractions determined. The compositional uniformity of the frac- (ions was improved by the finer grinding of the nitrite and nitrate salts, but not sufliciently for the required standards, as shown in Table IV.

The following Table V shows that a substantially uniform composition may be made by very fine grinding of a 906-4 composition No. 7. However, such a fineground mixture cakes and is commercially unsatisfactory. Table V shows the particle-size-distribution in percent for each fraction and the nitrite content of each fraction.

20 According to the presentinvention, a fine-ground caking mixture such as Composition No. 7 (Table V) can be compacted or agglomerated into caked forms, which caked forms may be comminuted to particle sizes coarser than the original mass. Compaction is illustrated by use of 25 those ingredients of which the particle-size-distribution is shown in Table I. Compositions Nos. 8, 9 and 10 were made with the ingredients of Table I, and were compacted and then ground to sizes having particle-size-distributions with fractions of nitrite salt content shown in Table VI.

30 Table VI Percent Nitrite Salt in Fractions Composition N o.

NaCl 011 On 100 On 200 Thru 200 8-; Finc 6.9 0.4 3.5 47 Fine Flake" 6. l 5. 8 4.3 5.8 Flake 6. 4 6. 0 4. 7 4. 8

The nitrite uniformity of Table VI does not meet said Federal standards, but it is greatly improved over that shown in Table II.

The present invention may be used to eliminate the tendency to cake of a mixture such as Composition N0. 7 of Table V. The finely ground Composition No. 7 was divided into four batches. These were compacted dry, with 1% added water, with 2% added water, and with 4% added water. The four compositions were then dried to not more than 1% moisture and ground to a size coarser than the original mass. The four dried comminuted compositions of -64 haveweight-fractions with nitrite content as shown in Table VII.

Table VII Particle Size Composition Percent On 50 On 100 On 200 Thru 200 0 {Percent Content.. 54 28 5 13 Percent Nitrite 6. l0 5. 99 6. 05 G. 05

1 Percent Content 61 1 24 4 10 Percent Nitrite 6. 05 6.06 5. 5. 95

2 Percent Content.. 55 24 '7 14 Percent Nitritem. 6. 06 5. 98 6.05 6.05

4 {Percent 0ontent 57 23 7 13 Percent Nitrite 6.03 5.99 6.04 6.02

Table IV Percent Nitrite Salt in Fractions Oomposition N o.-

N aCl On 50 On 100 On 200 Thru 200 Fine 5. 7 5. 1 3. 9 7. 0 Fine Flake 5. 6 4. 1 3. 6 7.6 Flake 5. 0 4. 5 4. 4 8. 2

The mesh data shown in Table V -is typical of a fine grind which will cake on standing, while themesh data of Table VII shows a particle-size-distribution' of sufiicient coarseness so that the composition is free-flowing indefinitely.

The compositions shown 'in Table VII were compacted between rolls urged together by a force of 5400 pounds per linear inch of roll. In Table VIII below, the same- Composition No. 7 ofTable V was compacted at a higher pressure corresponding to a force of 9000 pounds per linear inch of roll, otherwise using the same conditions. The products of Table VIII are also acceptable. Tables VII and VIII showthat with a suitably fine original mix- Table VIII Particle Size Another illustration of the effect of water is shown in TablesXI and XII. A composition 90-6-4 is ground to the size shown in Table XI, haying fractions which are non-uniform in nitrite content.

Table XI Mesh Percent Salt Percent Nitrite Composition Percent On 50 On 100 ture, the pressure of compaction and'the content of water are notcritical. w

Experience has shown that as the original mix ismade TableXII shows the sizes and nitrite content of the above mixture of Table XI, compacted dry and with 2% added water, and then dried and ground, all under the coarser, the tendency is to make unacceptable products, sameconditions exceptas to water.

Table. XII

Particle size Comlprositron Pgcent .On 50 011100 On 200 Thru 200 25 {Percent Content. 46 15 17 22 Percent Nitrite; 5.80 5. 55 4.10 6; 90

26 2 {Percent Content 55 16 14 16 Percent Nitrite 5. 80 6:05 5. 6. 15

and-that this tendency may be compensated for by increasing the moisture content, or by increasing the pressure, or by both. This is shown in Tables IX and X.

Table 1X shows a coarseroriginal mix than is shown in Table V.

. Table IX Percent in Fractions Composition No. 26 is acceptable in uniformity. From the foregoing it is to be understood that the trends for a uniform product are (l) the finer the grind of the factor shifts the ranges for the other factors.

Mesh Although it is preferable to grind the compacted ma- Salt Nitrite terial to a par-ticle-size-distribution which is coarser-than 0 2 .that of the original mass for certain uses, it may be dezz' "1'65 sirable to grind it to a form finer than that of the original Thmzoo mixt re for other uses. The references herein to the a partlcle-size-distribution of the original mass must -be In Table X, Compositions Nos. 23 and 24 are sub stantially'uniform in chemical composition in all. size fractions.

7 considered in connection withthe fact that during compaction crystals are fractured by the high pressure in order to produce forms .to fill the 'intercrystal voids.

' Table X Particle Size Composition .No. 11 0 Pressure 0 0 on Th n i n m 50 100 200 200 v 1 Percent Content" 16 0 9,000. Percent Nitrite.-. 6.60 1 9 000 {Percent Content" 21 t Percent lelitrttein 22.60

Percent on .en a 2 9100 igementlgitrtte 3.25

ercen on an I 0 500 {percent reun te 2(5i'65 -ercen en en 1 15500 {gercent lIitrtitmtn 23.65

ercen on en 500 gercent I(:Iitriite t 3g.

ercen on on 4 14,500 {Percent Nitrite.-. 5.80

1 Force in pounds per linearinch of roll.

Since it is. not possible to determine the extent to which the original mixture is thus changed in particle size by compaction, it is obvious that the pressure employed .in compaction fractures to a greater extent as the pressure is increased. Therefore, in using, say a coarser mixture and very high pressure, the result may be the same as some other circumstance in which a finer original mixture and a lower pressure are employed.

By specifying that the bonded cakes are reduced to a granular form coarser than the original mixture, it is practically assured that the desired uniformity of composition in the size-fractions will be achieved, because of the fracturing of the original mixtureto smaller size by compacting as described above. 1

The invention is not limited in saleable products to those which contain the entire product of grinding a compacted mass. Since the final product has fractions of graded sizes, any grind may be fractionated to select from its fractions a composition of one or more fractions Within a predetermined range of particle sizes. Such fractions as are rejected in doing this may be used as a raw material for recycling through the compaction procedure, whether they be at the coarser end or at the finer end.

In consequence, the original mass may be, or may include, particles which are aggregates of the component salts.

The-invention is not limited to mixing the separate crystals of sodium chloride, separate crystals of nitrite salt, and separate crystals of nitrate salt. However, that is preferred because such salts are commercially available to supply the raw materials. The presence of a limited amount of water is preferred to facilitate the bonding. The nitrite and nitrate salts are more readily dissolved by added Water than are the sodium chloride crystals.

Thus, the original mixture when compacted may con- The nitrite and nitrate salts may be combined into i a physically homogeneous fusion product, and that product used to supply the two salts.

The following Table XIII gives the fusion points of such salts, and of certain mixtures thereof.

Table XIII Approxi- Substance mate Melting Point, 0.

Potassium ni r 337 Potassium nitrite 297. 5 Sodium nitrate 308 Sodium nitrite 271 Sodium chloride.. 804 d' 't t 607 o rum m r1 e 0 Sodium nitrate 40% 230 Mixed:

Sodium nitrite 60%. Potassium nitrate 40%.

Begins to melt at 126 and is completely liquid and transparent at 156 Mixed:

Potassium nitrite 60%. Sodium nitrate 40%.

Begins to melt at 139 and is completely liquid and transparent at 172 There are some peculiar facts about the fusion points of mixtures. When dry nitrites and nitrates are mixed for fusion, the melting point is sharp when the same metal base, such as sodium, is used in both salts. When the metal bases differ, the melting point is spread over a wide range. This is believed due to a shifting of the equilibrium between the two salts forming perhaps four salts. It is also noted that where the metal bases differ the melting point is lower than when the metal base is the same for both salts.

The following example shows the invention practiced with a fusion to provide a 90-6-4 composition.

A solid fusion of 6 partsof sodium nitrite and 4 parts of sodium nitrate is mixed with 90 parts of sodium chloride. The two components may be separately ground, or the mixture may be ground so that all passes a l00-mesh screen. The fine ground mass is then compacted to cake form. When the irregular caked forms are desired in a granular free-flowing state, they are so ground that all passes a 30-mesh screen, 50% remains on a SO-mesh screen, and about 10% passes a ZOO-mesh screen. Such fractions are substantially uniform in nitrite content.

In carrying out the invention, the caked forms need 7 not be ground or comminuted to produce a granular product, there being no limit to the maximum size. For example, the chopping off of pellets from a continuous extrude can be accomplished so that the pellets, being fractured caked forms, are all of substantially the same size, so as to form a granular mass. When pellets are so formed, any water in the pellets may be removed thereafter, and then if sizes smaller than said pellets are desired the dried pellets may be reduced to the desired granular form. When a free-flowing granular form is desired, the caked forms may be ground to coarse sizes, even such as rock salt, to serve the mechanical purposes of the'users. It is noted, however, that the invention has been explained and exemplified by reference to an ultimate fineness much greater than need be practiced.

A granularform of curing salt of moderate fineness is the form desired by the meat packers, not only for mixing it directly in products for ground meat and for rubbing onto meat, but also for ready weighing and dissolution in forming brine.

The composition which is the subject of the present invention may contain additives, such as cane sugar, corn sugar, phosphate salts, alkaline agents, and seasoning, which function in the treatment of meat.

The invention is not limited to or by the details and examples given above to illustrate and explain the invention, and numerous changes and modifications are contemplated as falling within the scope of the invention as expressed in the appended claims.

This application is a continuation-in-part of Serial No.

' 209,216, filed July 11, 1962, now abandoned.

' which mass is substantially uniform in composition by combining with a major proportion of homogeneous sodium chloride crystals a-minor proportion of salt selected from the group consisting of alkali-metal nitrite, alkalimetal nitrate, and mixtures thereof, the sodium chloride being present in amount not over that to be used with the curing salt content, bonding said mass to cake forms by application of effective mechanical pressure, and reducing the size of said caked forms which have not more than 2% by weight of water to provide a granular mass of compaction-bonded agglomerates of such particle-sizedistribution that all the size-fractions thereof have a substantially uniform content. V

2. The method of claim 1 in which the caked forms are substantially dry when reduced in size.

3. The method of claim 1 in which said initial mass is characterized by a particle-size-distribution of which the size-fractions are non-uniform in chemical content.

4. The method of claim 1 wherein the initial mass contains from 1 to 4% by weight of water.

5. The method of claim 1 in which said selected salt comprises physically homogeneous particles thereof.

6. The method of claim 1 in which said initial mass is formed from physically homogeneous particles of said selected salt and from 1 to 4% by weight of water.

7. The method of claim 1 in which the initial mass is in finely divided granular form and in which the caked forms are reduced in size to a particle-size-distribution much coarser than said mass. 7

8. The method of claim l'in which the selected salt comprises separate crystals of alkali-metal nitrite and of alkali-metal nitrate.

9. The method of claim 1 in which the selected salt comprises particles of a physically homogeneous fusion mass of alkali-metal nitrite and alkali-metal nitrate.

10. The methodwhich comprises forming an initial free-flowing finely-divided granular curing salt mixture of substantially uniform composition, which composition comprises salt components consisting essentially of a major proportion of homogeneous sodium chloride crystals and a minor proportion of physically homogeneous particles of salt selected from the group consisting of alkali-metal nitrite, alka1irnetal nitrate and mixtures thereof, the sodium chloride being present in amount not over that to be used with the curing salt 'content, said I salt, bonding said mixture to caked forms of the same composition by application of efiective mechanical pressure, and reducing the size of said caked forms to a granular mass of compaction-bonded heterogeneous agglomcrates of different physically homogeneous particles which of Water in excess of 2% is present in the mixture sub-- jected to mechanical pressure, and in which the caked forms are dried to not over 2% of moisture for reducing the sizes thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,054,624 9/36 Grifiith 99-159 X 2,054,625 9/36 Grifiith 99-159 X 2,054,626 9/36 Griflith 99-159 2,145,417 1/39 Hall 99-222 2,400,292 5/46 Dalton. 2,668,770 a 2/54 Hall 99-159 X 2,668,771 2/54 Hall 99-159 X 2,770,548 11/56 Hall et a1. 99-159 X 2,770,549 11/56 Hall 99-159 X 2,770,550 11/56 Hall et a1. 99-159 X 2,770,551 11/56 Hall et a1. 99-159 X 2,828,212 3/58 Sair 99-159 X 2,935,387 5/60 Phillips 71-64 X 2,977,214 3/61 McLellan 71-64 3,098,767 7/63 Bush 127-63 A. LOUIS MONACELL, Primary Examiner.

HY MAN LORD, Examiner. 

1. THE METHOD OF PRODUCING A CURING SALT COMPOSITION WHICH METHOD COMPRISES FORMING AN INITIAL FREE-FLOWING PARTICULATE MASS HAVING UP TO 4% BY WEIGHT OF WATER WHICH MASS IS SUBSTANTIALLY UNIFORM IN COMPOSITION BY COMBINING WITH A MAJOR PROPORTION OF HOMOGENEOUS SODIUM CHLORIDE CRYSTALS A MINOR PROPORTION OF SALT SELECTED FROM THE GROUP CONSISTING OF ALKALI-METAL NITRITE, ALKALIMETAL NITRATE, AND MIXTURES THEREOF, THE SODIUM CHLORIDE BEING PRESENT IN AMOUNT NOT OVER THAT TO BE USED WITH THE CURING SALT CONTENT, BONDING SAID MASS TO CAKE FORMS BY APPLICATION OF EFFECTIVE MECHANICAL PRESSURE, AND REDUCING THE SIZE OF SAID CAKED FORMS WHICH HAVE NOT MORE THAN 2% BY WEIGHT OF WATER TO PROVIDE A GRANULAR MASS OF COMPACTION-BONDED AGGLOMERATES OF SUCH PARTICLE-SIZEDISTRIBUTION THAT ALL THE SIZE-FRACTIONS THEREOF HAVE A SUBSTANTIALLY UNIFORM CONTENT. 